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	<id>https://nethackwiki.com/index.php?action=history&amp;feed=atom&amp;title=Parasitology</id>
	<title>Parasitology - Revision history</title>
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	<updated>2026-07-21T16:12:25Z</updated>
	<subtitle>Revision history for this page on the wiki</subtitle>
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	<entry>
		<id>https://nethackwiki.com/index.php?title=Parasitology&amp;diff=199801&amp;oldid=prev</id>
		<title>Umbire the Phantom: potholes</title>
		<link rel="alternate" type="text/html" href="https://nethackwiki.com/index.php?title=Parasitology&amp;diff=199801&amp;oldid=prev"/>
		<updated>2026-02-27T12:06:58Z</updated>

		<summary type="html">&lt;p&gt;potholes&lt;/p&gt;
&lt;table class=&quot;diff diff-contentalign-left&quot; data-mw=&quot;interface&quot;&gt;
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				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;← Older revision&lt;/td&gt;
				&lt;td colspan=&quot;2&quot; style=&quot;background-color: #fff; color: #222; text-align: center;&quot;&gt;Revision as of 12:06, 27 February 2026&lt;/td&gt;
				&lt;/tr&gt;&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l1&quot; &gt;Line 1:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 1:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;In [[dNetHack]], [[notdNetHack]] and [[notnotdNetHack]], '''parasitology''' is a research path available to characters that have the weed [[thought]] slotted and with at least 27 [[insight]], necessary to activate the thought.[[Neutral]] [[Undead Hunter]]s start each game with the thought already slotted. It is also referred to as '''the philosophy of [[the choir]]'''.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;In [[dNetHack]], [[notdNetHack]] and [[notnotdNetHack]], '''parasitology''' is a research path available to characters that have the weed [[&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;Thought (item)|&lt;/ins&gt;thought]] slotted and with at least 27 [[insight]], necessary to activate the thought. [[Neutral]] [[Undead Hunter]]s start each game with the thought already slotted. It is also referred to as '''the philosophy of [[the choir]]'''.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Description==&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;==Description==&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot; id=&quot;mw-diff-left-l5&quot; &gt;Line 5:&lt;/td&gt;
&lt;td colspan=&quot;2&quot; class=&quot;diff-lineno&quot;&gt;Line 5:&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Upgrades are not linear, and may be chosen any number of times, except &amp;quot;visions of Yog-Sothoth&amp;quot;. Once enough research has been performed, a character may obtain a parasitology upgrade by [[apply]]ing a [[trephination kit]] with a parasite held in open inventory:&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;Upgrades are not linear, and may be chosen any number of times, except &amp;quot;visions of Yog-Sothoth&amp;quot;. Once enough research has been performed, a character may obtain a parasitology upgrade by [[apply]]ing a [[trephination kit]] with a parasite held in open inventory:&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt;−&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Suck out your enemies' brains: Adds a 1d2 [[intelligence &lt;del class=&quot;diffchange diffchange-inline&quot;&gt;drain&lt;/del&gt;]]&lt;del class=&quot;diffchange diffchange-inline&quot;&gt;ing &lt;/del&gt;attacks to your [[melee]] attack routine per parasite.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt;+&lt;/td&gt;&lt;td style=&quot;color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Suck out your enemies' brains: Adds a 1d2 [[intelligence&lt;ins class=&quot;diffchange diffchange-inline&quot;&gt;-draining&lt;/ins&gt;]] attacks to your [[melee]] attack routine per parasite.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Empower charm spells: Increases your [[skill]] with [[enchantment spells]]. Increases the odds of taming a monster for the [[charm monster]] spell for every third time this upgrade is taken. Decreases [[spell failure]] for enchantment spells by another 5%.&lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Empower charm spells: Increases your [[skill]] with [[enchantment spells]]. Increases the odds of taming a monster for the [[charm monster]] spell for every third time this upgrade is taken. Decreases [[spell failure]] for enchantment spells by another 5%.&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;tr&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Empower explosive spells: Increases the amount of [[ray]]s produced by ray spells.  &lt;/div&gt;&lt;/td&gt;&lt;td class='diff-marker'&gt; &lt;/td&gt;&lt;td style=&quot;background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;&quot;&gt;&lt;div&gt;* Empower explosive spells: Increases the amount of [[ray]]s produced by ray spells.  &lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;
&lt;/table&gt;</summary>
		<author><name>Umbire the Phantom</name></author>
		
	</entry>
	<entry>
		<id>https://nethackwiki.com/index.php?title=Parasitology&amp;diff=198178&amp;oldid=prev</id>
		<title>Klepto: created page.</title>
		<link rel="alternate" type="text/html" href="https://nethackwiki.com/index.php?title=Parasitology&amp;diff=198178&amp;oldid=prev"/>
		<updated>2026-01-27T03:18:44Z</updated>

		<summary type="html">&lt;p&gt;created page.&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;In [[dNetHack]], [[notdNetHack]] and [[notnotdNetHack]], '''parasitology''' is a research path available to characters that have the weed [[thought]] slotted and with at least 27 [[insight]], necessary to activate the thought.[[Neutral]] [[Undead Hunter]]s start each game with the thought already slotted. It is also referred to as '''the philosophy of [[the choir]]'''.&lt;br /&gt;
&lt;br /&gt;
==Description==&lt;br /&gt;
To progress along the research path, a character must [[research]] [[corpse]]s of non-[[mindless]], non-[[animal]] [[monster]]s at [[workbench]]es, or with a [[dissection kit]]. Corpses that have been researched, or that ''haven't'' been researched and [[Corpse#Aging|decayed]], may yield a number of [[parasite]]s, which are required to obtain parasitology upgrades. For non-Undead Hunters, following the parasitology research path requires [[wish]]ing for the thought and dissection kit.&lt;br /&gt;
&lt;br /&gt;
Upgrades are not linear, and may be chosen any number of times, except &amp;quot;visions of Yog-Sothoth&amp;quot;. Once enough research has been performed, a character may obtain a parasitology upgrade by [[apply]]ing a [[trephination kit]] with a parasite held in open inventory:&lt;br /&gt;
* Suck out your enemies' brains: Adds a 1d2 [[intelligence drain]]ing attacks to your [[melee]] attack routine per parasite.&lt;br /&gt;
* Empower charm spells: Increases your [[skill]] with [[enchantment spells]]. Increases the odds of taming a monster for the [[charm monster]] spell for every third time this upgrade is taken. Decreases [[spell failure]] for enchantment spells by another 5%.&lt;br /&gt;
* Empower explosive spells: Increases the amount of [[ray]]s produced by ray spells. &lt;br /&gt;
* Multi-shoot ray and beam spells: Increases the amount of [[explosion]]s produced by explosion spells. &lt;br /&gt;
* Sting adjacent enemies: Adds a 1d1 passive [[Intense pain|pain-inflicting]] tentacle attack per parasite. Makes 1 attack roll against every adjacent monster, and another for every third parasite rounding up. Each attack has a flat {{frac|2}} chance of skipping out on the attack. The stingers also only make at most 2 attacks per monster for every implanted parasite. &lt;br /&gt;
* Embrace the visions of Yog-Sothoth: Allows Undead Hunters to ask for the &amp;quot;windows to other places&amp;quot; Yog-Sothoth boon without meeting lifetime devotion thresholds, and any number of times. The upgrade can only be selected once&lt;br /&gt;
&lt;br /&gt;
All parasitology upgrades, except &amp;quot;visions of Yog-Sothoth&amp;quot;, decrease spell failure rate of all spells by 5%.&lt;br /&gt;
&lt;br /&gt;
Undead Hunters that wish to ascend under [[the Choir]], must have claimed at least 6 upgrades to achieve a [[score|full-scoring]] [[ascension]]. Other roles can obtain parasitology upgrades, but cannot ascend under an Undead Hunter ascension.&lt;br /&gt;
&lt;br /&gt;
Obtaining any upgrade also reduces current and peak [[intelligence]] and [[wisdom]] scores by 1. Every third upgrade taken on the research path will also permanently reduce the maximum intelligence and wisdom possible for that character by 1; this also stacks with reductions from [[defilement]] research. Fully advancing along the parasitology research path will reduce their intelligence and wisdom maximums by 4, producing a cap of 21 for each compared to the normal 25.&lt;br /&gt;
&lt;br /&gt;
The spells considered &amp;quot;advanced explosion&amp;quot; for the purposes of the table below are [[Spellbook of firestorm|firestorm]], [[Spellbook of blizzard|blizzard]] and [[Spellbook of lightning storm|lightning storm]].&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot; &lt;br /&gt;
! colspan=4| Rays and explosions gained per parasite:&lt;br /&gt;
|-&lt;br /&gt;
! Parasites: !! Advanced explosion spells !! Explosion spells !!  Ray spells&lt;br /&gt;
|-  &lt;br /&gt;
| 1 || +1 || +1 (50%) || +1 (50%)&lt;br /&gt;
|- &lt;br /&gt;
| 2 ||  +2 || +1 || +1&lt;br /&gt;
|-&lt;br /&gt;
| 3 ||  +3 || +1 + 1 (33%) || +1 + 1(33%)&lt;br /&gt;
|-&lt;br /&gt;
| 4 ||  +4 || +1 + 1 (66%) || +1 + 1 (66%)&lt;br /&gt;
|-&lt;br /&gt;
| 5 ||  +5 || +2 || +2 &lt;br /&gt;
|-&lt;br /&gt;
| 6 ||  +6 || +2 +1 (33%) || +2 +1 (33%)  &lt;br /&gt;
|-&lt;br /&gt;
| 7 ||  +7 || +2 +1 (66%) || +2 +1 (66%)&lt;br /&gt;
|-&lt;br /&gt;
| 8 ||  +8 || +3 || +3&lt;br /&gt;
|-&lt;br /&gt;
| 9 ||  +9 || +3 || +3&lt;br /&gt;
|-&lt;br /&gt;
| 10 ||  +10 || +3 +1 (25%) || +3 +1 (25%) &lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
==Messages==&lt;br /&gt;
{{message|You leave a seam so the parasite's radula can reach out.|You implanted a brainsucker.}}&lt;br /&gt;
{{message|You put the parasite in your medial prefrontal cortex.|You improved your enchantment spellcasting skill.}}&lt;br /&gt;
{{message|You put the parasite in your speech center.|You increased the amount of explosions produced by spells.}}&lt;br /&gt;
{{message|You put the parasite in your motor cortex.|You increased the amount of rays produced by spells.}}&lt;br /&gt;
{{message|You leave the parasite's stinging guard tentacles sticking out.|You implanted a jellyfish stinger.}}&lt;br /&gt;
{{message|You put the parasite in your corpus callosum.|You obtained the Yog-Sothoth upgrade.}}&lt;br /&gt;
&lt;br /&gt;
===Enlightenment messages:===&lt;br /&gt;
{{message|You have positioned &amp;lt;number&amp;gt; parasites to suck out your enemies' brains.}}&lt;br /&gt;
{{message|You have positioned &amp;lt;number&amp;gt; parasites to empower your charm spells.}}&lt;br /&gt;
{{message|You have positioned &amp;lt;number&amp;gt; parasites to empower your explosive spells}}&lt;br /&gt;
{{message|You have positioned &amp;lt;number&amp;gt; parasites to empower your ray and beam spells}}&lt;br /&gt;
{{message|You have positioned &amp;lt;number&amp;gt; parasites to sting adjacent enemies}}&lt;br /&gt;
&lt;br /&gt;
{{variant-343}}&lt;br /&gt;
[[Category: dNetHack research]]&lt;br /&gt;
[[Category: notdNetHack research]]&lt;br /&gt;
[[Category: notnotdNetHack research]]&lt;/div&gt;</summary>
		<author><name>Klepto</name></author>
		
	</entry>
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